Interesting. We just went through this process over the last few months. We love our 2012 slide-in Hawk (especially after I added an inside shower, extra drawers and converted over to the side dinette option) but we were still looking for the "sweet spot" for us as a couple. Soooo...
Two weeks ago we placed an order with "The FWC King of the Flat Beds", Denny Saunders up in Jackson, WY for a fairly tricked out Hawk Flatbed.
Jack brackets only (We don't plan to ever remove the Hawk but you never know. I'm not getting the stands yet because I don't want to store them!)
2-way frig 110 liter (ridiculously expensive but we LOVE the exact same one we have in our Hawk now.)
Furnace
Extra roof vent (We'll then upgrade to two of those fancy Fantastic Fans with the rain sensor)
Side Awning
Exterior LED lighting
Thermal pack
Aux. Battery System
2nd Deep Cycle Battery (I may swap these out for something better. Just totally confused on the whole solar/battery thing so I'm not installing anything yet.)
Self contained option(Hot water, Showers, Cassette Toilet)
Exterior Gas Struts (I can still put up our Hawk roof as of now but at 62...)
That's it. In September we'll be having a custom aluminum flat bed mounted (our current Hawk will be for sale then) and the new Hawk arrives mid-October!
I will say the Hawk FB has a lot more open space due to the extra 11" at the back and the extra space you gain by using the area of a normal PU's sidewalls.
My two cents,
Steve